For some time, known hot and cold water mixing valve devices for spouting and shutting off a mixture of hot and cold water in which hot water supplied from a hot water source and cold water supplied from a cold water source are mixed have included, for example, those in which an external casing creating the external appearance of a mixing valve device is a cast-molded product.
In the conventional hot and cold water mixing valve set forth in this Patent Document 1 (Japanese Patent Unexamined Publication No. 6-313490 (Heisei)), a cylindrical mixing valve device main body is housed within a cylindrical external casing, being a cast part, and this mixing valve device main body includes a cylindrical external casing tightly adhering to the outside casing, and a cylindrical inside casing installed in a watertight manner inside this outside casing.
A mixing valve cartridge for mixing hot and cold water, and a switching valve cartridge for switching between spouting and shutting off water from the tap and controlling the amount of spouted water, are respectively housed in a watertight manner and affixed inside the inner cartridge.
I.e., in the above-described conventional hot and cold water mixing valve device, a plurality of O-rings are respectively installed between the exterior casing and the outside casing of the mixing valve device main body on the inside thereof, between the outside casing of the mixing valve device main body and the inside casing on the inside thereof, and between the inside casing of the mixing valve device main body and the mixing valve cartridge and switching valve cartridge on the inside thereof. During assembly, the mixing valve device main body is inserted from one of the openings at the two end portions in the longitudinal direction of the cylindrical outside casing, being a cast-formed part, and after sliding to a predetermined housing position inside the outside casing in a tightly adhered state mediated by the inner surface of the outside casing and the O-ring, the mixing valve device main body is affixed in a watertight manner inside the outside casing.
In addition, because internal passages for hot and cold water are formed by housing and holding of the mixing valve device main body inside the external casing, no special mechanical machining is required to provide an internal passage, thereby simplifying the hot and cold water mixing valve device manufacturing process, even though the external casing is a cast-molded part.
However, for the above-described conventional hot and cold water mixing valve device, required specifications in some cases differ due to various differences in installation conditions between Japan and overseas regions.
For example, depending on installation conditions, in some cases a longer than normal specification for the exterior dimension in the longitudinal direction of the hot and cold water mixing valve device is used, or a longer specification is used for the axial center distance between the hot water inlet and the cold water inlet of the hot and cold water mixing valve device (the distance between the central axis of the hot water inlet and the central axis of the cold water inlet in the hot and cold water mixing valve device); in these cases, the distance over which the hot and cold water mixing faucet is slid up to a predetermined housing position in the external casing after being inserted from the opening at one end in the longitudinal direction of the external casing is lengthened when assembling the hot and cold water mixing valve device.
Hence the longer the inter-axis distance between the hot water inlet and the cold water inlet on the hot and cold water mixing valve device or the outside diameter dimension of the valve device main body in the longitudinal direction, the greater the potential that the O ring between the inside surface of the external casing and the valve device main body will slip off the specified watertight position due to rubbing resistance during assembly, damaging the watertightness of the valve device main body interior; as an additional problem, the condition of the interior such valve device main bodies cannot be visually inspected from the outside.